At present, with the increase of size and resolution of a LCD panel, the problem of uneven luminance of a display screen is more and more prominent. At present, the main technology for solving the problem of the uneven luminance of a display screen is an optical compensation technology, and the optical compensation technology is based on the acquisition of luminance data of the display screen. In the related art, the acquisition of the luminance data of the display screen is mainly performed by obtaining luminance information of the screen using an area array image sensor (CCD) by a distance, and then calibrating luminance data by a point luminance meter. The advantage of this kind of luminance data acquisition method lies in that the way of obtaining data is convenient and quick, but there are also obvious defects in this kind of acquisition method. As the increase of the size of the display screen, the distance from the CCD to the display screen needs to be increased. Thus, the image resolution collected by the CCD is reduced, and the collected image is also prone to generate a moire pattern or is affected by other light sources, resulting in a lower accuracy of the resulting full-screen luminance data.